Timeline
- 1899/1900: Self-loading pistols test: Colt M1900 of .38 caliber entered.
- 1904: Thompson-LaGarde Tests—caliber of new handgun should be at least .45.
- 1906–1907: Handgun trials—Colt enters with .45 ACP design.
- 1910: Final tests—Colt pistol (designed by John Browning) out-performs Savage.
- March 29, 1911: The Colt pistol is officially adopted as the Model 1911—and with it, the .45 ACP cartridge.
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